Contact spring



M. FRITTS CONTACT SPRING Feb. 26, 1952 Filed Aug. 25, 1949 INS UL A TION INSULA 1'10 5 onm7 M A T TOR/V5 Y Patented Feb. 26, 1952 CONTACT SPRING Morris Fritts, Chatham, N. J., assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a'corporation of New York Application August 25, 1949, Serial No. 112,191

7 Claims.

This invention relates to electric circuit controlling apparatus and more particularly to the contact-making elements thereof.

In the controlling of electrical circuits, means in the form of switches, relays, keys, etc., are frequently employed to complete or interrupt the circuit paths. The contact elements thereof must complete the circuits with minimal impedance at the point of contact. Inemciencies frequently arise in applications of these devices from three major causes: improper engagement of the mating contacts due to malalignment thereof, foreign matter such as dust between the mating contacts, and vibration leading to the well-known contact chatter. These deficiencies have been appreciably reduced through the use of a pair of contacts engaging a single mating contact as is shown, for example, in the appli-.

cation of H. C. Harrison, Serial No. 993, filed January '7, 19%8. The present invention improves upon this previous advance in the art'by providing a structure in which the twin contacts are essentially self-aligning and self-pressure adjusting while retaining the advantages obtained from the use of twin contacts. The present invention further effectively eliminates the problem of obtaining and maintaining parallelism between the adjacent long spring members and permits an appreciable saving of material. The invention permits a whereby without removing the apparatus from its mounting and without disabling the apparatus but for a short time, the contacts and the vcontrolling members therefor may be replaced with elements of different contact materials or controlling members of'different configuration to change the combination of make and break contacts.

object of this inventionis to provide. twin electrical 'contacts with a single flexible wire supporting member therefor. 7

Another object of this invention is to provide readily removable and replaceable contact members and controlling members therefor.

In general, the preferred embodiment of the ready interchangeability of parts invention comprises a plurality of single-wire supporting springs molded or otherwise affixed in a-base member in a cantilever fashion. Twin contacting members are provided for each of these springs. Each of these members preferably comprises a wire member looped back on itself to form the two contacting elements. This wire member is thenmolded in or otherwise aflixed to a controlling member of insulating material, frequently referred to as a card,

This insulating controlling member is the means by which the contacts associated therewith are maintained in a stationary position or are actuated. The assembly comprising the contact members and the insulating controlling member therefor is then associated with the single Wire supported spring. In the preferred embodiment, this is accomplished by inserting the supporting springs in apertures in the controlling members with the bights of the contact members engaging the supporting spring. Each supporting spring may be provided with a detented portion at the point of contact withthe bight of the contact as they appear prior to assembly; and

Fig. 4 discloses a partially cut away view of the elements of Fig. 2 as they appear when assembled and demonstrates the use of solder to more permanently associate the parts if desired.

Referring now to Fig. l, the exemplary contact assembly comprises an upper portion and a lower portion. The upper portion comprises a base member ll of insulating material of any suitable shape'and size'into which is clamped, molded or otherwise affixed a plurality of wire supporting springs [2. These supporting springs l2 are flexible, wire, current-carrying members and may be extended to the rear of the base 'member H to provide wiring terminals. Mounted at the anterior end of-each supporting spring I2 is a U-shaped contact member l3 which is also of relatively flexible wire. The bight I4 of each U-shaped contact member 13 engages the associated supporting spring I2 and is in firm electrical and mechanical contact therewith. As will be seen hereinafter, at the point of engagement between the bight Hi of each contact member l3 and its associated supporting spring i2, the latter may be provided with a detented portion 15. Associated with a group of contact members [3 is a controlling member 16 of insulating material. This member may be provided with suitably spaced apertures into which the contact members l3 are inserted, may comprise two mating sections which are clamped over the contact member I3, or may be molded directly on a group of contact members id. The insulating controlling member It may be of any ap propriate shape in accordance with the confer mation of the other elements of the apparatus of which the contact assembly is to be a parta Apellf tures are provided in the controlling member It in plane with the contact members I3 and at points intermediate each pair of points at which the two arms on each contact member 53 extend through the controlling member. These apertures accept the supporting springs I2 and are preferably of substantially the same diameter asthose springs to provide a tight engagement therewith.

Referring now to Fig. 2, it willbe seen that the assembly comprising the contact members I3 and the controlling member I6 is readily removable from the supporting spring I2. Thus, in any apparatus, the assembly comprising the controlling member I6 and the contact members I3 may be replaced, either for the purpose of providing a controlling member of different peripheral configuration or to provide contact members of different material. As is apparent in Fig. 2, the contact members I3 preferably lie in a single plane, and in that plane apertures I! are provided in controlling member I6 intermediate the tWo arms of each of the contact members as above mentioned. In assembling the elements of Fig. 2, the anterior ends of the supporting springs I2 are inserted in aperture II. If, as is preferable, the supporting springs I2 are provided with detented portions I5, it is desirable that adjacent supporting springs be detented in opposite vertical direction. Thus, in Fig. 2, the rearmost and forwardmost supporting springs I2 are detented as at I so that the bights Ill. of the associated contact members I3 rest on top of the supporting springs when they are cradled in the detented portions of those springs, while the middle supporting spring I2 is detented so that that spring rests on top of the bight HI of the associated contact member I3 when the apparatus is fully assembled. The depth of the detent I5 is preferably equal to or slightly less than the diameter of the wire of the contact members I3 as shown in Fig. 4, in which a portion of the contact member I3 has been cut away for purposes of clarity. Therefore, when the elements of Fig. 2 are assembled, the contact members I3 exert forces on adjacent support members I2 in opposite directions thereby providing an integral assembly which will resist accidental relative movement. A low impedance electrical connection between the supporting spring I2 andthe contact members I3 is thereby insured.

As shown in Fig. 4, if desired, the bights I4 of the contact members I3 may be afiixed within the detents I5 of the supporting springs I2 by means of solder It to provide additional assurance of the electrical and mechanical integrity of the elements.

Referring now to Figs. 1 and 3, the lower portion of the assembly is substantially identical to the upper portion as above described, and comprises a base member. IS, a plurality of supporting springs 29, a double contacting member 2| for each supporting spring, and an insulating controlling member 22 associated with groups of said springs. The interassociation of thecontact members, controlling members and supporting springs is preferably identical with that of the upper portion. The lower portlqll. diners contact members 2|.

from the u per portion in that theconfi' uration of the controlling members 22 willnormally' be different than that of the controlling members I 6 and in that the contact member's 2I are prop= erly conformed to mate with the contact members I3. This may be accomplished by forming each of the lower contact members 2| so that .the two arms thereof are separated more widely than are the corresponding arms of the upper contact members I3, i. e., so that when the elements are completely assembled, the arms of the upper contact members I3 do not lie in the same vertical planes with the arms of the lower To provide engagement between the contact members, the outermost ends of the lower contact members 2| may be bent towards. each other at right angles to the arms of those members thereby providing a contact surface which will mate with the arms of the associated upper contact members I3 either when the upper controlling member 18 is .forced downwardly or when the lower controlling member 22 is forced upwardly. It will be obvious to one skilled in the art that the arms of each of the lower contact members 21 may be spaced more closely than the arms of each of the upper contact members I3 with the outermost ends of the arms of the lower contacting member 2| being bent outwardly to provide a contact sur face. It will also be apparent that the contact members I3 and 2i may be provided with addi tional mating precious-metal contacts if desired.

The controlling members I6 or 22 may be as= sociated with only one of the spring members I2 or 29 if desired, although an association with more than one spring member has been found to be advantageous in view of the above-discussed considerations. It has also been found expeditious to make the supporting springs I2 or 20 of slightly differing lengths to aid in the aligning of these members with the appropriate apertures in the associated control member.

It will be noted that by critical location of the detents in the supporting springs and by manufacturing control of the positioning of the contact members in the controlling members, the elements are essentially self-aligning and self-pressure adjusting in assembly, a feature which permits ready interchangeability without the necessity of critical testing of the assembled result.

It is to be understood that the above-described arrangements areillustrative of the application of the principles of the invention. Numerous other arrangements may be devised by those skilled in the art without departing from the spirit and scope of the invention.

What is claimed is:

1.v In a contact spring assembly, a controlling memberof insulating material, a U-shaped contact member physically connected thereto, and a supporting spring physically engaging said controlling member and continuously engaging said contact member.

2. In a contact spring assembly, a controlling member of insulating material, a U-shaped contact member supported therein, and a round wire supporting spring inserted in an aperture in said controlling member and engaging the bight of said U-shapedcontact member.

3. .In .a contact spring assembly, a single wire spring and means for providing two separate contact elements therefor, said means comprising a u-shaped wire. contact member having two arm portions parallel to the axis of said single wire spring and a bight portion. engaging said.

single wire spring, and a controlling member of insulating material having apertures therein through which the arms of said contact member and said single wire spring extend.

4. In a contact spring assembly, a base member of insulating material, a plurality of round wire springs supported therein and extending therefrom, a controlling member of insulating material removably mounted on said wire springs, and a plurality of contact members, each of said contact members comprising a U-shaped wire supported in said controlling member and having a bight portion firmly engaging an as sociated one of said wire springs.

5. In a contact spring assembly, a controlling member of insulating material having three apertures therein, a U-shaped wire contact member having a bight portion and two arm portions, the arm portions of said contact member engaging two of the apertures in said controlling member, and a wire supporting member removably engaging the other aperture in said controlling member and having a detented portion engaging the bight of said contact memher.

6. In a contact spring assembly, a first and a second controlling member of insulating material each having a plurality of apertures therein, a plurality of U-shaped wire contact members each having a bight portion and two arm portions, the arm portions of each of certain ones of said'contact members engaging apertures in said first controlling member, the arm portions of each of certain others of said contact members engaging apertures in said second controlling member, and a plurality of wire supporting springs, certain of said springs engaging apertures in said first controlling member and the bight portions of said certain ones of said contact members, certain others of said springs engaging apertures in said second controlling member and the bight portions of said certain others of said contact members.

7. In a contact spring assembly, a first and a second controlling member of insulating material each having a plurality of apertures therein, a plurality of U-shaped wire contact members each having a bight portion and two arm portions, the arm portions of each of certain ones of said contact members engaging apertures in said first controlling member, the arm portions of each of certain others of said contact members engaging apertures in said second controlling member, and a plurality of wire supporting springs, certain of said springs engaging apertures in said first controlling member and lying in plane with certain ones of said contact members and having detented portions engaging the bight portions of said certain ones of said contact members, certain others of said springs engaging apertures in said second controlling member and lying in plane with said certain others of said contact members and having detented portions engaging the bight portions of said certain others of said contact members.

MORRIS FRITTS.

REFERENCES CITED The following references are of record in the file of this patent:

' UNITED STATES PATENTS Number Name Date 1,037,767 Hoge Sept. 3, 1912 2,442,500 Lamb June 1, 1948 2,517,679 Knos Aug. 8, 1950 

